No, you have it slighly wrong.
It is the sum of the scores of the opponents you beat, plus half the sum of the scores of the opponents you drew against.
[edit] maybe I misunderstood, the above is for tiebreaks.
Your method is exactly right for the main score.
I posted this question in a forum about calculating tie breaks butt I did not get an answer. How is the basic score for a tournament calculated? For OTB tournaments it is the number of wins plus 1/2 the number of draws. That doesn't seem to work here. I know of many cases where that is not the score. So what's up? Is it a different system, or is it a glitch?